The invention relates to an electronic chip type component installation structure, and more particularly to a structure for installing chip type electronic components on a printed substrate having fitting patterns by soldering.
For instance, when fitting chip type electronic components such as laminated capacitors and chip resistors on a printed substrate, it is common to use an installation structure that provides a fitting pattern 3 on a printed substrate 1 at a fitting position of an electronic component 2, and fit and fix electrodes 4 of the component 2 to the fitting pattern 3 by solder 5, as shown in FIGS. 10 to 13.
On the installation structure, it was inevitable to use a large quantity of solder 5 in the case of a close arrangement between the chip type electronic component 2 and a chassis 6 as shown in FIGS. 10 and 11 or in the case of a parallel arrangement between plural electronic components 2, 2 as shown in FIGS. 12 and 13.
The thicker the solder layer between the electronic components 2, 2, the bigger the thermal expansion and contraction of the solder. This will thus tend to cause cracks of the electronic component 2 and failure of their soldered portions.
The conventional way to solve these problems was to widen the distance between the electronic component 2 and the chassis 6, or between the adjacent electronic components 2, 2, as shown in FIGS. 14 and 17, corresponding to a widening of the fitting pattern 3, and paint a resist film 7 so as to separate the patterns 3 and reduce the respective solder quantity 5, as shown in FIGS. 14 and 16.
But the problem is such that the band of resist film 7 across and over the fitting pattern 3 causes a lack of solder 5 due to the reduction of the soldering area. This weakens the required fitting strength and the electric connection of electronic component 2. On the contrary, excessive solder may rise upon the resist film 7 and break the insulation of the resist film.
The shortage of solder may also make the soldering impossible due to the lowering polarity of solder 5 between the electrode 4 and the electronic component 2, thus rendering the resumption of soldering necessary.